A Light-Weight Operating System for Internet of Things Devices Emekcan Aras Embedded Computing Systems Submission date: June 2016 Supervisor: Amund Skavhaug, ITK Norwegian University of Science and Technology Department of Engineering Cybernetics A Light-weight Operating System for Internet of Things Devices Emekcan Aras June 2015 PROJECT / MASTER THESIS Department of of Engineering Cybernetics Norwegian University of Science and Technology Supervisor: Associate Professor Amund Skavhaug i Preface This master thesis was written the spring of 2016 at the Norwegian University of Technology and Science, Departmen of Engineering Cybernetics. It has been a part of my master program EMECS( European Master in Embedded Computing Systems) and this thesis concludes my Mas- ter’s degree. This Master’s thesis is a contribution and new way of look to embedded operating systems. It is not the continuation of the specialization project of the fall semester 2015 even if the overall goal of developing the robust wireles networks still stands. This thesis has not been submitted previously and has been made by independent work. In addition, a conference paper is being written based on this paper which focus more on IOT service layer. The thesis can be divided into two important parts. The first part is developing a very small “microscopic” operating system. The design steps and background lies behind the design is explained in detail in this particular paper. The second part is radio communication protocol and IOT service layer which is presented as the novelty of the project. Since there are many different operating system and architec- ture can be found in the market, we have revealed that a specific embedded operating system designed for IOT and wireless sensor networks that enables resource and information sharing, would be a good research topic. Therefore, the particular project can be considered as the col- lection of the related background education, embedded software skills, hours of discussions and sparks of new ideas about embedded operating systems. This particular paper has been written for three types of readers. The one who would like to read and learn something about operating systems and embedded system, the students who would like to continue the project and the professors who will asses this paper. Trondheim, June 2016 Emekcan Aras ii Acknowledgment I have now spent two years in abroad since I left Istanbul for this Joint Degree program. I have lived in two beautiful cities Southampton and Trondheim and I have found to chance to meet with wonderful people in these years. I will soon be graduated and leave Trondheim but I will never forget this period of my life. I would like to thank my friends in EMECS program who have worked hard with me and never hesitate to help me for anything. In addition, I would like to thank my beloved friends in Istanbul, Glasgow, Berlin and Milano who gave me the inspiration to apply this program and supported me during it, we may live away from each other but they will never be forgotten. I would like to thank my supervisor professor Amund Skavhaug for the help, guidance and invaluable ideas he has given during the semester. Lastly, I would like to thank my beloved father and mother who always supported me during this program and taught me that another world without any war or discrimination is possible. E.A. iii Summary and Conclusions Nowadays, all around of us has been surrounded by wireless devices. More than a decade, engi- neers have been using these wireless devices in industry to measure environmental data. Large networks, which are formed by hundreds or thousands sensor nodes, are not easy to build, maintain and observe. Moreover, with the trending concept called Internet of Things, devices have gained different functionalities and the different type of networks started to develop. In order to design an efficient and low cost sensor and IOT network, a different type of architecture in both network side and low-level software side must be developed. Designing a specific operating system motivated us earlier part in this project. After detailed investigation, it is revealed that resource-constrained embedded devices need a new type of embedded operating system specifically developed for sensor and IOT network. Moreover, in the market, there are many choice for embedded operating systems. However, an open-source operating system for embedded devices in the sensor and IOT networks is needed and could be useful for educational purposes as well as commercial purposes. In the light of the motivations that is mentioned at the paragraph above, a light-weight em- bedded operating system has been designed and developed from scratch in this thesis. In addi- tion to that, a radio protocol and an IOT service layer which act as middleware in the network have been designed and implemented into the embedded operating system. All the background lies behind this project and the designing steps are explained in detail in this thesis. In addition to this, a conference paper about the operating system particularly IOT service layer is being written. Keil uVision5 software development platform was used to develop the mentioned operating system in this project. Detailed investigation and research were done about embedded systems, operating systems, distributed systems and wireless communication before the project. After- wards, entire software libraries for the kernel and hardware drivers were developed from scratch by using C and Assembly language. Since the project is focused on embedded devices, one of the low-power processor architectures called ARM Cortex-M0 architecture has been used as the target platform. An SOC from Nordic Semiconductor called NRF51822, which contains this pro- cessor architecture, is used inside of the devices in this project. In order to test and validate the iv results and functionality of the system, two different development kits have been used provided by the vendor company. Detailed tests scenarios have been tried and a small working sensor network/cluster has been formed by using these devices and the operating system. At the end of the project, a small size operating system which requires around 8Kb of flash memory and 7Kb of RAM, has been created. Tasks which is given to devices has been efficiently executed without causing any overhead or failure. In addition to this, functionality which is provided by the IOT layer has been achieved as well. Two types of device are introduced with the proposed IOT layer. A standard component for sensor and IOT networks called “node de- vice” and supervisor component of the network called “manager device” are tested. After tests and verifications, it has been seen that resource and information sharing across the network is achieved. In this thesis project, resource-constrained low profile embedded devices and architectures selected as the target device group. It is revealed that using a specifically design operating sys- tem, these types of devices could be used in many applications with reasonable prices. More- over, the proposed operating system layer could bring a new way of thinking on the sensor and IOT device networks and could be used as the solution for problems and challenges. Further- more, with the user-friendly design particular operating system could be very useful in educa- tional purposes. List of Abbreviations and Symbols IOT Internet of Things RAM Random Access Memory CORBA Common Object Request Broker Architecture SOA Service Oriented Architecture OSI Open System Interconnection OS Operating System API Application Porgramming Interface HAL Hardware Abstraction Layer CPU Central Processing Unit TCP IP Transmission Control Protocol-Internet Protocol SOC System on Chip TI Texas Instruments RTOS Real-Time Operating System ROM Read-Only Memory GUI Graphical User Interface IPC Inter-process Communication v vi RF Radio Frequency VLF Very Low Frequency EHF Extremely High Frequency ASK Amplitude Shift Keying PSK Phase Shift Keying FSK Frequency Shift Keying PRN Pseudo-Random-Noise DSSS Direct Sequence Spread Spectrum FHSS Frequency Hopping Spread Spectrum ISM Industrial Scientific Medical IO Input-Output GPIO General Purpose Input-Output PCB Printed Circuit Board RSSI Received Signal Strength Indication AES Advanced Encryption Standard CRC Cyclic Redundancy Check DMA Direct Memory Access I2C Inter-Integrated Circuit SPI Serial Peripheral Interface PSP Process Stack Pointer MSP Main Stack Pointer vii ISR Interrupt Service Routine SVC Service Call RISC Reduced Instruction Set Computing MIPS Microprocessor without Interlocked Pipeline Stages List of Figures 1.1 Prediction about IOT devices [5]...............................3 1.2 A survey about Internet of Things 1 [8]...........................6 1.3 A survey about Internet of Things 1 [8]...........................7 2.1 A general structure of Embedded Systems [9]....................... 12 2.2 Monolithic System Architecture [12]............................ 14 2.3 Layered System Architecture [13].............................. 15 2.4 Microkernel Architecture Structure [12].......................... 16 2.5 Difference between Client-Server and Multi-Tier Architecture............ 20 2.6 Implementation of CORBA................................. 21 2.7 Structure of SOA........................................ 22 2.8 OSI model [19]......................................... 23 2.9 Frequency Ranges [20].................................... 24 2.10 Types of Digital Modulation [21].............................